The semiconductor device industry has experienced rapid growth. In the course of device evolution, the functional density has generally increased while feature size has decreased. This scaling down process generally provides benefits by increasing production efficiency and lowering associated costs. Such scaling down has also increased the complexity of design and manufacturing these devices.
One of the many techniques used to produce semiconductor devices is photolithographic patterning or photolithography. Photolithography is a process by which a pattern produced on a photomask can be transferred to a photoreactive material layer (photoresist or PR), which when developed includes a pattern corresponding to the pattern produced on the photomask. Thereafter, the patterned photoresist layer may serve as an etch mask during an etch process to pattern the material layer underneath the photoresist layer.
As the scaling down of semiconductor devices has progressed, conventional photolithography has not proved entirely satisfactory. New techniques, such as extreme ultraviolet (EMU) photolithography, have allowed the scaling to continue, but there are still significant difficulties to be overcome. For example, providing a patterned photoresist layer with sufficient structural integrity to withstand one or more etchings may result in a patterned photoresist layer that is difficult to remove from the semiconductor device wafer in order to perform subsequent processing steps.